How to buy sustainable fish

The short answer

There is no single most sustainable fish, because it depends on where it came from and how it was caught or farmed. The reliable way to choose is to check the species and its source against the Marine Conservation Society Good Fish Guide, buy what is in season and ask your fishmonger where a fish came from. A good counter will tell you and will point you to a better swap if there is one.

What makes a fish sustainable

Three things matter more than the name of the fish.

• The stock it came from. The same species can be healthy in one sea and overfished in another. Cornish and North Sea and Icelandic stocks are all different populations.
• How it was caught or farmed. Some methods have far less impact on the seabed and on other species than others. Farming standards vary widely too.
• Whether the population can keep up. A well-managed fishery replaces what is taken. An overfished one does not.

This is why sustainability is a question about a specific fish from a specific source, rather than a fixed list of good and bad species.

Use the MCS Good Fish Guide

The Marine Conservation Society runs the Good Fish Guide, the main independent UK reference for seafood sustainability. It rates fish from 1 to 5, where 1 and 2 are the responsible choices, 3 is a fish to think about and 4 and 5 are ones to avoid. The rating depends on the species, the sea it came from and the method, so the same fish can carry different ratings depending on its source. You can check any fish on the guide at goodfishguide.org. We use it as our reference too.

What to ask at the counter

You do not need to memorise ratings. Ask us.

• Where is this fish from?
• Is there a more responsible choice today for what I want to cook?
• What is good and in season right now?

We will give you a straight answer, and if a fish is a better choice for the same dish we will say so. That conversation is the whole point of buying from a counter.

Buy what is in season

Seasonality is one of the easiest ways to eat more responsibly, because a fish caught in season tends to come from a healthier, better-managed supply and eats better too. British waters give you different fish through the year.

• Spring: crab starts to come good, along with plaice and sea trout.
• Summer: mackerel, sardines, sea bass and crab.
• Autumn: mussels return, along with oysters and hake.
• Winter: oysters, mussels and firm white fish for hearty cooking.

Ask us what is in season when you visit, because it changes week to week.

Simple habits that help

• Widen your range. Trying less familiar fish such as hake, gurnard, coley, dab or mussels takes pressure off the few species everyone buys.
• Buy the amount you will eat. Cutting to order and pricing by weight means less waste, which is a sustainability gain in itself.
• Use the whole fish. Ask for the bones and trimmings for stock.

A note on claims

We will not tell you a fish is certified as something it is not. Where a specific certification or rating applies we will point you to it, and where a fish is simply British catch from a source we know, we will say exactly that and no more. If sustainability matters to you for a particular meal, ask before you buy and we will help you choose. Ask at the counter or order for delivery.

Frequently asked questions

What is the most sustainable fish to eat? There is no single answer, because it depends on the source and the method. As a rule, fish rated 1 or 2 on the MCS Good Fish Guide are responsible choices. Mussels, oysters and some British hake and mackerel often rate well, but always check the specific source.

Is cod sustainable? It depends entirely on where it came from. Cod from some well-managed stocks rates well, while cod from overfished areas does not. Check the source on the MCS Good Fish Guide, or ask us where ours is from.

What is the MCS Good Fish Guide? It is the Marine Conservation Society's independent guide to seafood sustainability. It rates fish from 1 to 5 based on the species, the area it came from and how it was caught or farmed. You can search any fish at goodfishguide.org.

How do I know the fish I buy is responsibly sourced? Ask your fishmonger where it came from and how it was produced, and check the species and source against the MCS Good Fish Guide. A counter that can answer those questions is doing the work for you.

Is farmed fish sustainable? It varies with the farm and its standards. Some farmed fish is a responsible choice and some is not. Ask about the source, and check the rating for that specific product.

What fish is in season in the UK right now? It changes through the year and week to week. Ask us what is in season when you visit and we will point you to it.

Featured photograph by Mutney, licensed CC BY 4.0, via Wikimedia Commons.